What changed in Minecraft 17w43a

Key	Text
key.apostrophe	'
key.backslash	\
key.backspace	Backspace
key.caps.lock	Caps Lock
key.comma	,
key.delete	Delete
key.down	Down Arrow
key.end	End
key.enter	Enter
key.equal	=
key.escape	Escape
key.f1	F1
key.f10	F10
key.f11	F11
key.f12	F12
key.f13	F13
key.f14	F14
key.f15	F15
key.f16	F16
key.f17	F17
key.f18	F18
key.f19	F19
key.f2	F2
key.f20	F20
key.f21	F21
key.f22	F22
key.f23	F23
key.f24	F24
key.f25	F25
key.f3	F3
key.f4	F4
key.f5	F5
key.f6	F6
key.f7	F7
key.f8	F8
key.f9	F9
key.grave.accent	`
key.home	Home
key.insert	Insert
key.keypad.0	Keypad 0
key.keypad.1	Keypad 1
key.keypad.2	Keypad 2
key.keypad.3	Keypad 3
key.keypad.4	Keypad 4
key.keypad.5	Keypad 5
key.keypad.6	Keypad 6
key.keypad.7	Keypad 7
key.keypad.8	Keypad 8
key.keypad.9	Keypad 9
key.keypad.add	Keypad +
key.keypad.decimal	Keypad Decimal
key.keypad.divide	Keypad /
key.keypad.enter	Keypad Enter
key.keypad.equal	Keypad =
key.keypad.multiply	Keypad *
key.keypad.subtract	Keypad -
key.left.alt	Left Alt
key.left.bracket	[
key.left.control	Left Control
key.left.shift	Left Shift
key.left.win	Left Win
key.menu	Menu
key.minus	-
key.mouse	Button %1$s
key.num.lock	Num Lock
key.page.down	Page Down
key.page.up	Page Up
key.pause	Pause
key.period	.
key.print.screen	Print Screen
key.right.alt	Right Alt
key.right.bracket	]
key.right.control	Right Control
key.right.shift	Right Shift
key.right.win	Right Win
key.scroll.lock	Scroll Lock
key.semicolon	;
key.slash	/
key.space	Space
key.tab	Tab
key.unknown	Not bound
key.up	Up Arrow
key.world.1	World 1
key.world.2	World 2
options.fullscreen.current	Current
options.fullscreen.resolution	FS Resolution
resourcePack.server.name	World Specific Resources

Key	Before	After
key.left	Strafe Left	Left Arrow
key.mouse.left	Left Click	Left Button
key.mouse.middle	Middle Click	Middle Button
key.mouse.right	Right Click	Right Button
key.right	Strafe Right	Right Arrow